Curiosity Rover finds “treasure chest” full of crystals on Mars
A selfie of NASA’s Curiosity Rover on Mars.
On May 30, scientists were amazed when a rock being driven over by NASA’s Mars rover Curiosity cracked open, revealing something never seen before on the Red Planet: a treasure chest—or, in geological terms, a geode—full of yellow crystals.
Since August 2012, Curiosity has been exploring Gale Crater, a large basin in the equatorial region of Mars. Billions of years ago, this impact crater hosted a shallow lake, as shown by fossilized wave tracks and the Sulfate-Bearing Unit, a sedimentary rock formation rich in sulfur-bearing minerals (a mixture of sulfur and other elements) that were deposited when water evaporated.
Using an instrument on the rover’s arm, scientists later determined that the yellow crystals were elemental sulfur. It was the first time this type of crystalline sulfur had been found on the Red Planet.
These yellow crystals were exposed after NASA’s Curiosity accidentally drove over a rock and broke … [+]
It is not clear if and how the sulfur geode is related to other sulfur-containing minerals in the area. On Earth, elemental sulfur forms only under very limited conditions. Sulfur crystals can form by the oxidation of hydrogen sulfide at the edges of volcanic vents that emit hot gases and vapors. So far, however, Curiosity has found no evidence of past or current volcanic activity at this site. Sulfur is also found in some vein deposits and as a chemical alteration product of older sulfur-containing minerals. Pure sulfur in sedimentary rocks can form by the reduction of sulfates (sulfur-oxygen minerals) – and is of interest to the search for life on Mars – through microbial activity.
Pure sulfur crystals from Sicily, formed by the crystallization of volcanic gases.
Scientists also believe that elemental sulfur is more common in Martian rocks than previously thought. Nine days earlier, Curiosity had discovered a whole field of bright rocks similar to the one the rover had accidentally crushed.
Curiosity captured this close-up image of a rock nicknamed “Snow Lake,” which resembles the rock … [+]
“Finding a field of rocks made of pure sulfur is like finding an oasis in the desert,” explains Curiosity project scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Southern California. “It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”
Additional material and interviews provided by NASA.
